The present invention relates to an air bag device comprising a horn switch, and, more particularly, to an air bag device which is constructed so that, when a module cover is pushed, only a module cover moves so as to turn on the horn switch.
There is a type of driver-seat air bag device installed at the steering wheel of an automobile, which is constructed so that, when a module cover of the air bag device is pushed, a horn switch is turned on in order to blow a horn. In this case, when the air bag device is constructed so that only the module cover, and not the entire air bag device, moves to turn on the horn switch, only a small amount of pushing force is required to turn on the horn switch.
An airbag apparatus 100 having such a structure is shown in FIG. 7. The airbag apparatus 100 comprises a retainer 102, an airbag 106 attached to the retainer 102 with an airbag fitting ring 104, an inflator 108 for inflating the airbag 106, and a module cover 110 for covering the folded airbag 106.
An integral leg section 112 protrudes from the back side of the module cover 110, and hooks 116 of a side-wall section 114 which is bent forward from the retainer 102 are inserted through openings 118 in the leg section 112. Each hook 116 outwardly protrudes from the sidewall section 114 in an L-shape.
The inflator 108 includes a flange 108a. Bolts 120 protruding from the ring 104 are inserted through the retainer 102 and the flange 108a, so that the inflator 108 is fixed to the retainer 102 together with the airbag 106 by tightening nuts 122.
The shape of the folded airbag 106 is maintained by a shape holding member 124. The shape holding member 124 allows the airbag 106 to expand by breaking-off or deforming when the airbag 106 is inflated.
A bracket 132 protrudes upwardly from a steering wheel 130, and projecting pieces 134 protruding downward from the backside of the retainer 102. The pieces 134 are fixed to the bracket 132 with bolts 136 and nuts 138.
A predetermined sized gap is formed between the back face of the module cover 110 and the shape holding member 124. A predetermined sized gap is also formed between the opening 118 formed on the leg section 112 of the module cover 110 and the hook 116. As a result, the module cover 110 can be moved vertically. When the module cover 110 is pressed, a horn switch (not shown) is pressed so as to be turned on. The horn switch is integrally formed with the retainer 102 and attached to an extending portion extending from the retainer 102.
In the driver-seat air bag device, when the inflator is actuated to inflate the airbag, the module cover is torn along a tear line due to the force applied from the inflating airbag. Then, a large force is exerted on the module cover in the direction in which the module cover is separated from the retainer.
In a conventional air bag device which has its module cover firmly secured to its retainer, the module cover does not separate away from the retainer. However, in an air bag device which is constructed so that the module cover moves in a direction in which it comes into contact with and separates from the retainer, the hook 116 may get dislodged from the opening 118 of the leg 112 of the module cover.
The present invention is directed to overcoming or at least reducing the effects of one or more of the problems set forth above.
Accordingly, it is an object of the present invention to provide an air bag device which makes it possible to reliably retain a module cover by a retainer during the expansion of an air bag (that is, during the operation of an inflator), when the air bag device is of a type whose module cover can move in a direction in which it comes into contact with and separates from the retainer.
According to the present invention, there is provided an air bag device comprising an air bag; a retainer to which the air bag is mounted; a module cover which covers the air bag, the module cover being movable towards the retainer; a wall projected from the retainer; a leg projected downwardly from an underside of the module cover; an opening formed in the leg; and a hook protruded from the wall, the hook extending into the opening; wherein the opening and the hook are separated by a space which allows movement of the module cover; and wherein a restricting member for restricting the movement of the leg in a direction in which the leg separates away from the wall is provided at the retainer.
In such an air bag device, in the case where the module cover is torn followed by operating the inflator, even when the leg of the module cover tries to separate away from the wall of the retainer, the restricting member prevents the separation of the module cover away from the wall of the retainer. Therefore, the hook is not dislodged from the opening in the leg at all.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.